Knife sheath



FIG. 1 is a perspective view of a knife sheath showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a side view thereof; and,

FIG. 7 is an opposite side view. 

The ornamental design for a knife sheath, as shown. 